1. Field of the Invention
The present invention relates to a switch unit to be used for operating various devices such a powerwindow unit mounted on a vehicle such as a motor vehicle.
2. Description of the Related Art
A powerwindow unit up/down-operates a window glass installed at a door trim of a vehicle. Based on an operation signal from a switch unit provided on the door trim, the powerwindow unit drives a motor and so on for up/down-operating the window glass, thereby open and close a window.
The above switch unit has a knob as a operative body which is swingingly operably provided, a printed circuit board, a decorative members to cover the printed circuit board and to make the knob exposed. A first contacting member facing the printed circuit board is provided on one end portion of the knob. A second contacting member facing the printed circuit board is provided on the other end portion of the knob.
Between the first contacting member and one end portion of the knob provided are a returning spring and a pressing pin, which pressing pin presses the first contacting member toward the printed circuit board when one end portion of the knob is pushed toward the printed circuit board. Also, between the second contacting member and the other end portion of the knob provided are a returning spring and a pressing pin, which pressing pin presses the second contacting member toward the printed circuit board when the other end portion of the knob is pushed toward the printed circuit board. On the other hand, each returning spring return the knob in an initial state.
First and second contact portions to face the respective first and second contacting members are mounted on the printed circuit board. And, a supporting axis is laterally provided on a generally longitudinal middle portion the knob.
According to the above-described structure of the conventional switch unit, when one end portion of the knob is pushed toward the printed circuit board, the first contacting member is pressed through the pressing pin and comes into contact with the first contact portion. Then, this first contact portion outputs a signal, for example, to raise the window glass toward the powerwindow unit.
When the other end portion of the knob is pushed toward the printed circuit board, the second contacting member is pressed through the pressing pin and comes into contact with the second contact portion. Then, this second contact portion outputs a signal, for example, to raise the window glass toward the powerwindow unit.
And, when the pushing operation of one end portion or the other end portion of the knob is removed, one end portion or the other end portion of the knob returns to each initial state by means of each returning spring, whereby the output signal from each contact portion stops.
With respect to the above-described conventional switch unit, however, when one end portion of the knob is pressed toward the printed circuit board, the other end portion turns about the supporting axis, while being apart from the printed circuit board. As a result, the other end portion of the knob fairly largely projects over the decorative member.
On the contrary, when the other end portion is pressed toward the printed circuit board, one end portion turns about the supporting axis, while being apart from the printed circuit board. As a result, the one end portion of the knob fairly largely projects over the decorative member.
Accordingly, in the conventional switch unit, the end portions of the knob each have to be thick enough not to make a vertical clearance between each of them and the decorative member, for example, for preventing dust or the like from coming into the switch unit, which requires a relatively large distance between the decorative member and the printed circuit board.
Consequently, the conventional switch unit has a relatively large thickness, which increases a setting space of the unit onto the door trim and restricts a design of the door trim.
Further, the conventional switch unit requires the pressing pin and the returning spring are necessary, which increases the number of parts, thereby lowering the efficiency of assembly work and raising the cost.